Sawmill-carriage-knee snubber



May as, 1929.

H. w. AMBROSE SAWMILL CARRIAGE KNEE SNUBBER Filed Oct. 10, 1927 ATTORN EY Patented May 28, 1929 UNITED HENRY w. AMBROSE, or CONWAY, SOUTH CAROLINA.

SAWMILL-CARRIAGE-KNEE SNUIBBER.

Application. filed October 10, 1827.

This invention relates to an attachment for a saw mill carriage, the general object of the invention being to provide means for taking lost motion out of the lever assembly of the knee of a carriage and also the rack and pinion thereof. 7

This invention alsoconsists in certain other features of construction and in the combination and arrangement of the several parts, to be hereinafter fully described, illustrated in the accompanying drawings and specifically pointed out in the appended claims.

In describing my invention in detail, reference will be had to the accoi'npanying drawings wherein like characters denote like or corresponding parts throughout the several views, and in which Figure 1 is a View partly in section of part of a carriage and its knee, showing the invention applied thereto,

Figure 2 is a section on line 22 of Figure 1.

ure 2.

Figure 4t is a view of the bracket attached to the knee lever and to which the chain is fastened which operates the lock rod.

In the drawings, the numeral 1 indicates the base or lower portion of the head block, 2 one of the knees and. 3 indicates a pinion on the shaft 4 for engaging the rack 5 of the knee for adjusting it transversely on the base or lower portion of the head block, when the shaft is turned. Each knee is also adjusted independently of the other knees by means of the taper lever 6 which is pivoted to the rear part of the knee at 7 and is connected by a link 8 to an ear 9 carried by the rack bar 5 which is slidably connected with the knee.

The lever is pivoted to the link at 10 and the other end of the link is pivoted to the car at 11.

The latch 12 for holding the lever 6 in adjusted position, as well as the pivotal points '7, 10 and 11 are subjected to wear and when this wear takes place, the knee will have considerable play and this play will result in irregular thickness of lumber being sawed by the mill, owing to the creeping ahead of the knees, one or more of them when the stroke of setworks is made. That is, the momentum of the knee and log will pull this lost motion, or to state it yet more plainly, the local conditions, such as freshly oiled grooves of knees and plates of bases, irregular steam pressure on the setworks and failure of operator to control the rising steam by means Figure 3 is a section on line of Figscrial No. 225,276.

provided, will often cause the knees to slide forwardly from the momentum of the stroke, as far as the lost motion in parts 6, 7 9 and. 10 will permit. I

Play also occurs between the pinion and rack, due to wear of these parts. In order to take up this lost motion or play as well as the lost motion in the taper lever, 1 place a pair of brackets "13 on the side of the knee and these brackets support a pair of guiding bars 14: for a cross head 15. A coil-spring 16 is placed on one or both of the guiding'rods, as required, and when properly tensioned, tends to move the cross head toward the front bracket. A spool 17 is fastened to the shaft 4 and a cable 18 has one end fastened to the cross head and its other end is fastened to the spool, the cable being wrapped a plurality of times around the spool. A small sheave 19 is carried by a depending part 20 on the rear end of the base or bottom portion of the head block and the cable passes around this sheave A lock bar 21 is pivoted to the cross head and has its free end bent downwardly, as shown at 22, to engage the rear bracket 13 for limiting the rearward movement of the cross head and thus lock the lost motion out of all joints above enumerated. This lock bar is adjustable as to its length, as shown at 23. A; cable or chain connects the free'end of this lock bar to a plate 25 which is fastened to the lever 6'so that when the latchis lifted out'of its seat, the chain will pull the lock rod upwardly, disengaging it, and thus permit independent movement of the knee. 7

From the foregoing, it will be seen that the tension of the spring 16 on the cross head will keep the cable taut, and exert tension at the pivotalpoints 7, 9, 10 andll and also.

upon the pinion and rack and thus take up lost motion from all the pivotal points of the lever connection and the rack and pinion.

,The amount of power exerted upon the knee to hold it back against sliding tendencies is governed by the amount of tension put in the spring. By relative sizes of the spool'and pinion which has been determined, they operate in perfect accord so that tension on spring remains the same as knees are movedback and forth on the bases, but by makingthat part of the spool upon which the cable winds of less diameter (about of an inch) than the root diameter of the pinion, the cable on the spool is not played off quite as fast as the knee moves in its forward motion, thus slightly increasing the pull on the knee as it moves forwardly step by step. This gradual increasing of the pull on the knee tends to offset any undue forward pull on the knee by springing timber.

The tension thus exerted on the knees does not cause any additionalload on setworks, for while the end of the cable attached to cross head of snubbers is pullingthe knee back, the other end of the cable attached to spool on set shaft-is pulling knee ahead with equal power.

As this device wholly eliminates lost'motion at the several points mentioned, no joint or'rack and piniongives further trouble hecause'of lost motion therein. Moreover, old head blocks are made to work even better than new ones'because the play or lost motion in the working parts is entirely eliminated, whereas new blocks will have some lost motion in them. t,-therefore, intended that these snubberswill make possible the cutting of more uniform lumber and a resultant saving in timber, for wide the elimination of the sliding ahead of the knees, it is POSFlblO to reduce the thicknessof wood used for cu t-ting a 4/4 board by of an'inchwhere 1 v of wood is used for saw kerf and board ft; willv give 1-boards when dry, thus saving on every stroke of the set works.

It is thought from the foregoing description that the advantages and novel features of my invention will be readily apparent.

It is to be understood that I may make' changes in the construction and in illlOCOlHlJlnation an d arrangement of the several parts, provided that such changesfall within the scope of the appended el aims.

\Vhat Iclaim is 1. Means for taking up lost'motion in the lever assembly and pinionand rack of a saw mill carriage comprising guides on a knee of a c arriage,a cross headv on the guides, a spool on the oinion shaft a sheave on the carriao'e at the rear of theiknee, a cable connected with the cross head and passing over the sheave at the rear of the knee and being wrapped several-times and fastenedto the spool on the shaft and spring means for holding the cross head in its forward position to hold the cable taut, the spool being smaller than the pinion whereby the cable is not pl ayed. off the spool as fast as the knee moves forwardly so as to slightly increase the pull on theknee as it moves :t'orwardly.

2. 'Means fortakingup lost motion inthe lever assembly'and pinion and rack of a saw mill carriage comprising guides on a knee of a carriage, a cross head on the guides a spool on the pinion shaft, a sheave on the carriage at the rear of the knee, a cable connected with the cross head and passing around the-sheave at the rear of the knee'and being wrapped several times and fastened to the spool on the shaft, spring means for holding the cross head in its forward position to hold the cable taut and a stop lever on the cross head for limiting the rearward movement of the same.

Means for taking up lost'motion in the lever assembly and pinion and rack of a saw mill carriage con'iprising guides on a knee of a carriage, a cross head on the guides, a spool on the pinion shaft, a sheave on the carriage at the rear of the knee, a cable connected with the cross head and passing over the sheave at the rear of the knee and being wrapped several times and fastenedto the spoolon' the shaft, spring means for holding the cross head in its for Jard position tohold the cable taut, a lock rod on the cross head for limiting the rearward n'iovement of the same and means connected with the h and lever of the knee for moving the look rod into inoperative position when the hand lever is shifted to movethe knee on the carriage. r

In testimony whereof I aflix my signature.

HEN Y w. AMBROSE. 

